The perfect burger

For chef Nancy Silverton, that means the right meat, peak-season tomatoes and a great bun. It's as easy -- and fabulous -- as it sounds.

Note: From Nancy Silverton. Silverton says burgers are the perfect party food because the toppings can be done in advance, then guests use them to personalize their burgers. Though she offers three cheeses, she says that from experience, most takers are for Gruyere, 25% might take cheddar and one of a group will want blue. Crumble out enough blue to look pretty in a bowl, 2 to 3 ounces, and know it may go into salad dressing for the next meal. Ditto cheddar, but this may fill an omelet. The cheeses should be good-quality, such as Point Reyes Blue, aged Gruyere and Grafton cheddar from Vermont or Fiscalini or Straus cheddar from California. The buns should be good-quality soft sesame or poppy seed hamburger buns. For the beef, ask the butcher to grind 2 3/4 pounds of prime chuck (10% to 15% fat) with 4 to 6 ounces of prime sirloin fat (the combination should have 20% to 28% fat total).

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Toppings

12 strips applewood-smoked

bacon

2 ripe avocados

1 teaspoon lemon juice

2 tablespoons snipped chives

Sea salt

Freshly ground black pepper

1 large, ripe heirloom tomato

1/2 red onion

3 ounces blue cheese

3 ounces cheddar

3 ounces Gruyere

6 iceberg lettuce leaves, each about 5 inches wide

Heinz ketchup

Best Foods mayonnaise (or Hellman's east of the Rockies)

Dijon mustard, smooth and coarse-grained

Pepperoncini

Dill pickles, sliced vertically in quarters or eighths

1. Fry the bacon in a hot skillet until done but not too crisp, about 8 minutes. Drain on paper towels and set aside.

2. Cut the avocados into quarters or sixths. Sprinkle lightly with lemon juice, add the chives and toss. Season with sea salt and pepper. Set aside in a serving dish.

3. Cut the tomato into slices about one-fourth-inch thick and season lightly with sea salt and pepper. Set aside. Cut the red onion into very thin (about one-eighth-inch) slices and season lightly with sea salt and pepper. Set aside.

4. Crumble the blue cheese and cheddar into separate serving bowls. Slice the Gruyere with a cheese plane onto a serving plate and set aside.

Burgers and assembly

6 large sesame or poppy seed hamburger buns

Extra virgin olive oil

About 3 pounds ground beef (see note)

3 teaspoons kosher salt

Freshly ground black pepper

1. Brush the cut side of each bun with olive oil and set aside. Light an outdoor grill or place a seasoned cast-iron skillet over high heat.

2. Being careful not to overwork the meat, shape it into 6 patties, about 2 inches thick and 4 inches in diameter. Sprinkle each side of each patty with about one-fourth teaspoon of kosher salt and 4 to 6 grindings of freshly ground black pepper.

3. Place the burgers on the hot grill or in the hot cast-iron skillet. Sear them until they can be turned without sticking, then turn them. For rare, cook about 4 minutes, then flip and cook another 4 minutes (for medium-rare, 5 minutes on each side; for medium, 6 minutes).

4. As the burgers are cooking, toast the buns, cut side on grill or pan, for a minute or two. Just before the burgers are done cooking, garnish with a little good-quality sea salt, then top with cheese and let it melt. Have guests place lettuce, onion, tomato, bacon and avocado on the bottom half of their toasted bun. Place the burger on top, then the top of the bun. Serve ketchup, mayonnaise, mustard, pepperoncini and dill pickles with burgers.